A few "Gotcha’s" are;* The HTML Content must be less than 8000 bytes, otherwise you get the error:

0x8004271A ODSOLE Extended Procedure Error in srv_convert.

* The COM object WinHttp.WinHttpRequest.5.1 must be installed on the server, some typical variations are WinHttp.WinHttpRequest.5and WinHttp.WinHttpRequest. A search for the CLSID in Regedit should find the one you are using.